Argonaute and RNA--getting into the groove.

RNAi has made an enormous impact on biology in a very short period of time. It became an extraordinarily useful and simple tool for gene silencing, even as its fascinating mechanism was gradually unraveling. Understanding the mechanism of RNAi-related pathways, including both transcriptional and posttranscriptional gene silencing and even processes such as DNA elimination in Tetrahymena, have benefited from an incredible marriage of genetics, biochemistry, molecular biology, bioinformatics and finally structural biology. Structural biology played a key role in deciphering the role that a central player--the Argonaute protein--has in all RNAi processes.